Qt工作笔记-对信号与槽的进一步理解（信号与信号关联）

运行截图如下：

关键代码如下：

    connect(ui->pushButton,SIGNAL(clicked(bool)),this,SLOT(btnClicked()));
    connect(this,SIGNAL(signal_1(QString)),this,SIGNAL(signal_2(QString)));
    connect(this,SIGNAL(signal_2(QString)),this,SIGNAL(signal_3(QString)));
    connect(this,SIGNAL(signal_3(QString)),this,SLOT(slot_3(QString)));

下面给出所有的代码

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

public slots:

    void btnClicked();
    void slot_3(QString msg);

signals:
    void signal_1(QString msg1);
    void signal_2(QString msg2);
    void signal_3(QString msg3);


private:
    Ui::Widget *ui;
};

#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"

#include <QDebug>

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setWindowTitle(tr("CSDN IT1995"));
    connect(ui->pushButton,SIGNAL(clicked(bool)),this,SLOT(btnClicked()));
    connect(this,SIGNAL(signal_1(QString)),this,SIGNAL(signal_2(QString)));
    connect(this,SIGNAL(signal_2(QString)),this,SIGNAL(signal_3(QString)));
    connect(this,SIGNAL(signal_3(QString)),this,SLOT(slot_3(QString)));
}

void Widget::slot_3(QString msg){
    ui->lineEdit->setText(msg);
}

void Widget::btnClicked(){
    emit signal_1(tr("CSDN IT1995"));
}

Widget::~Widget()
{
    delete ui;
}

main.cpp

#include "widget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}